Gravitational baryogenesis in energy-momentum squared gravity

Abstract

We investigate the phenomenon of gravitational baryogenesis within the context of a specific modified theory of gravity, namely, energy-momentum squared gravity or $f(R, T_{\mu\nu}T^{\mu\nu})$ gravity. In this framework, the gravitational Lagrangian is formulated as a general function of the Ricci scalar $R$ and the self-contraction of the energy-momentum tensor, $\mathcal{T}^2 \equiv T_{\mu\nu}T^{\mu\nu}$. This approach extends the conventional paradigm of gravitational baryogenesis by introducing new dependencies that allow for a more comprehensive exploration of the baryon asymmetry problem. Our analysis aims to elucidate the role of these gravitational modifications in the generation of baryon asymmetry, a critical issue in cosmology that remains unresolved within the Standard Model of particle physics. By incorporating $\mathcal{T}^2$ into the gravitational action, we propose that these modifications can significantly influence the dynamics of the early universe, thereby altering the conditions under which baryogenesis occurs. This study not only provides a novel depiction of gravitational baryogenesis but also offers insights into how modified gravity theories can address the longstanding question of baryon asymmetry. The implications of our findings suggest that $f(R, T_{\mu\nu}T^{\mu\nu})$ gravity could play a crucial role in understanding the fundamental processes that led to the matter-antimatter imbalance observed in the universe today.